This invention relates to a flexible coupling for rotatable shafts which incorporates back-up or fail-safe coupling means for the continuance of the transmission of rotary motion in the event of failure of the primary coupling means during the rotation of the drive shaft.
Numerous rotary shaft couplings have been developed or proposed but none has been found entirely satisfactory for certain critical uses having imposed limitations of weight, compactness and reliability as well as requirements of minimum lost motion and resistance to large temperature swings. Such critical use of rotary shaft couplings is encountered, for example, in aircraft engines where the couplings are exposed to vibration and must be flexible enough to accommodate small deviations from perfect alignment of the coupled shafts. In such critical use, a fail-safe construction is very desirable if not imperative.
Accordingly, the object of this invention is to provide a fail-safe flexible coupling for rotary shafts meeting unusual physical and performance requirements.